This invention relates to an injected internal combustion engine and more particularly to an air manifold and fuel rail mounting arrangement for such engine.
The use of fuel injection in place of carburetors is being widely accepted in most applications for internal combustion engines. One convenient and relatively low-cost type of injection system employs what is referred to as "manifold injection." With this type of arrangement, fuel is injected into the induction system preferably at a point quite close to the intake port of the engine.
With four-cycle engines, this generally means that the fuel injector is mounted in the cylinder head and injects fuel into the intake passage at a point that is located close to the intake valve seat and may, in fact, be directed directly toward that valve seat. This generally means that the fuel injector is mounted quite close to the area of attachment of the intake manifold to the cylinder head. This gives rise to certain problems in connection with the mounting of the various components to the cylinder head to ensure against interference between the various mounting arrangements.
It is, therefore, a principal object of this invention to provide an improved mounting arrangement for the components of a fuel injected, internal combustion engine.
It is a further object of this invention to provide an improved mounting arrangement for the components of a manifold injected engine where the fuel injectors spray into the cylinder head intake passages.
Frequently, it has been the practice to supply the fuel to the fuel injectors through a device that is referred to as a "fuel rail." A fuel rail is actually a form of manifold that delivers fuel from a high pressure source to the individual fuel injectors. Many times, it has been the practice to mount the fuel rail directly to the injectors and not attach it permanently to any component of the engine other than through its hydraulic connections to the fuel supply system. However, this can give rise to the likelihood or possibility of the fuel rail working itself loose, particularly if the engine is subjected to vibrations in use.
It has, therefore, been proposed to fasten the fuel manifold or fuel rail also to the engine body on which the fuel injectors are mounted. This obviously gives rise to further problems in connection with attachment of the components including the fuel rail.
It is, therefore, a further object of this invention to provide an improved arrangement for attaching a fuel rail to an engine.
It is a still further object of this invention to provide an improved mounting arrangement for the fuel rail of a manifold injected engine where the fuel rail is mounted in close proximity to the intake manifold attachment to the cylinder head.
Because of the fact that the fuel injectors are disposed generally at an angle to the portion of the intake passage which they intersect, in order to provide the desired flow direction, then the normal positioning of the fuel rail is such that its hold-down fasteners extend at a different angle to the associated surface of the cylinder head than the fasteners that hold the intake manifold in place. This requires sequential machining operations and adds to the cost of manufacturing the various cylinder head assembly.
It is, therefore, a still further object of this invention to provide an improved arrangement for holding down the fuel rail and intake manifold to a cylinder head of an engine wherein the threaded fasteners for each can extend along parallel axis to simplify machining.